Experimental and DFT investigation of (Cr,Ti)3AlC2 MAX phases stability

Materials Research Letters

Denis Horlait¹  William E. Lee²  Patrick A. Burr³ 

[1] CNRS/IN2P3 and University of Bordeaux, Centre d’Etudes Nucléaires de Bordeaux-Gradignan;Imperial College;University of New South Wales;

关键词: Quaternary MAX phase;    synthesis and characterization;    DFT simulations;    atomic ordering;   

DOI  :  10.1080/21663831.2016.1222598

来源: DOAJ

【 摘 要 】

Using a synergistic combination of experimental and computational methods, we shed light on the unusual solubility of (Cr,Ti)3AlC2 MAX phase, showing that it may accommodate Cr only at very low concentrations (<2 at%) or at the exact Cr/(Cr + Ti) ratio of 2/3, even when the ratio of reactants is far from this stoichiometry (1/2 ≤ Cr/(Cr + Ti) ≤ 5/6). In both phases, Cr exclusively occupies the 4f sites, bridging carbide layers with the Al layer. Despite this, the peculiar stability of (Cr2/3Ti1/3)3AlC2 is attributed to the formation of strong, spin-polarized Cr–C bonds, which result in volume reduction and a marked increase in c/a ratio.

【 授权许可】

Unknown